Method of making shuttle blocks



Patented Feb. 19, 1952 UNITED STATES PATENT OF F ICE METHOD'OF MAKING SHUTTLE BLOCKS John R'ossC'lIrtis, Nashot'ah, Wis

Application June 2, 1948, Serial-No.- 30,614

4 Claims.

The present invention relates to shuttleblocks and the process of making the same. The term shuttle block as used in this application has:

reference to rectangular block or the like, generally of wood, from which loom shuttles employed in the weaving industry are manufactured.

Loom shuttles are almost universally constructed of wood. Long experience has shown that wood is practically the only material that will give the proper contact or friction between the shuttle and the binders and the backs of the shuttle boxes to hold the shuttle from reboundingfrom the shuttle boxes. It has been suggested to make such shuttles from various other materials such as plastics and the like, but for numerous reasons they have been found to be inferior to wood-loom shuttles. In practice shuttles have been made substantially only from dogwood which has had art that a loom shuttle comprises a memberirithe form of an elongated loop with pointed ends- Such a shuttle is usually formed from a shuttle block of rectangular configuration and it is necessary to hollow out a substantial portion of the shuttle block in the manufacture of the shuttle to accommodate the bobbin.

Attempts have been made to densify wood to produce the desired hardness and other favorable characteristics of dogwood, but heretofore such attempts have been unsatisfactory as far as manufacturing shuttle blocks are concerned since the wood is densiiied throughout its construction thereby making it difficult to rout out the central portion of the shuttle block in manufacturing the shuttle to form the chamber for the bobbin.

It would be desirable to provide a new and improved shuttle block whereby loom shuttles may be manufactured therefrom, which shuttle block is formed of a wood other than dogwood while still retaining the desirable characteristics of dogwood.

Accordingly, it is an object of the presentinvention to provide a new and improved shuttle block.

It is another object of the invention: to provide a new and improved process of densifying wood.

It is a further object of the present invention to provide an improved process of densifying wood, particularly adaptable for producing shuttle 2. blocks from which loom shuttles may be manuf actured.

Still another object of the present invention is to provide a new and improved process of densifying wood whereby certain portions only aredensified and other portions. which it may be desirable to cutaway are notsubstantially densified.

Further objects and advantages of thepresent invention will become apparent asthe following description proceeds. and the features of novelty which characterize the invention will be pointed out with particularity in the claims annexed to and forming a. part of this specification.

For a. better understanding, of the: present in.- vention reference may be: had to the accompany ing: drawing in which:

Fig- 1 is a perspective view of a shuttle ofthetype commonly employed in the weaving industry;

Fig. 2- is a shuttle block constructed in: accordance with thepresent invention from which loom shuttles of the type shown in Fig. 1 may be manufactured;

Fig. 3 isa sectional view of an apparatus employed in carrying out the process of: the present invention showing shuttle blocks of the type shown in Fig. 2 in the process of construction;

Fig. 4 is. a sectional view taken on line i -4' of Fig. 3; and

Fig- 5 is a partial sectional view of a tank containing asolution in which shuttle block blanks are-immersed in accordance with one stepof the process of the present invention.

Although the process of the present invention for densifying wood may have general applica-- tion, it is particularly applicable to manufacturing shuttle blocks and. accordingly, for the pur-- pose ofdescribing and illustrating the present invention, the process-of manufacturing a shuttle block is specifically described. understood, however, that it is not intended to limit applicants invention solely to-shuttle blocks and the process of manufacturing the same.

Referring. nowto Fig; l of the drawings there is illustratedv a loom shuttle generally indicatedat It which forms no part ofthe present-invention, except that it may be manufactured from. the shuttle block of the present invention to be described in detail hereinafter. A loom shuttle such as I0: is generally formed of wood of: elongated configuration having pointed metal end tips II. The shuttle has an elongated chamber I2 which is hollowed out in the central portion of the shuttle to receive the conventional bobbin,

It should be not shown. The walls of the chamber 12 are designated by the reference numerals 12a and l2b. The loom shuttle is also provided with the usual means for supporting the spindle upon which the bobbinis to be placed. It will be observed that the wall portions In and l2b which are relatively thin should be and remain relatively smooth and to prevent being roughened requires that they be formed of a dense close grained wood.

As has been mentioned above, heretofore, loom shuttles such as I have been manufactured from shuttle blocks formed of dogwood, which shuttle blocks are of somewhat rectangular configuration as shown in Fig. 2 of the drawing. In accordance with the present invention the shuttle block generally indicated at G3 at Fig. 2"of the drawing is a rectangular block of wood such as maple, birch, beech or the like, which is relatively common and easy to obtain, compared with do wood, which has been densified only in certain portions in accordance with the process of the present invention so as to be especially suitable for manufacture of loom shuttles such as It].

In accordance with a preferred embodiment of the present invention for manufacturing a compressed wood .shuttle block, suitable pieces of wood such as hard maple, beech, birch, or the like, are employed which have been cut to a predetermined dimension. For a particular embodiment of the present invention hard maple blanks were employed having dimensions of 16 inches by 2% inches by 1 inches, which blanks preferably had a minimum weight of 1%; lbs. Preferably such blanks are air or kiln dried so that the moisture content is reduced to about 12%, although a higher moisture content is permissible. Also, the ends of the shuttle block blanks are preferably dipped in a hot wax to prevent checking during the interim between the cutting of the wood into the shuttle block blanks and the manufacture of the shuttle block to be described hereinafter. It is desirable that the shuttle block blanks do not contain any heart wood which has been found to be generally unsatisfactory.

The first step in the process of manufacturing shuttle blocks from blanks which are cut to a predetermined size, have a predetermined minimum weight, and a predetermined low moisture content is illustrated in Fig. 5 of the drawings, where the shuttle block blanks generally designated at 13' are immersed in a solution designated at M which is disposed within a suitable tank or container 15. The solution 14 is preferably "a solution of linseed oil, turpentine and a naphtha petroleum solvent having a high flash point. A suitable naphtha petroleum solvent for this purpose may be purchased on the market as APCO 467. It has been found preferable to make the solution M of equal parts of linseed oil, turpentine, and naphtha petroleum solvent. By immersing the blanks I3 in the solution Hi for a period of the order of two hours the solution penetrates into the blanks to a limited extent. During the heat and pressure step to be described hereinafter the solution is caused to penetrate relatively deeply into the wood. It is believed that the penetration of the solution l4 into the blanks tends to soften up the lignin in the wood so as to reduce the pressure required during the densifying step of the process.

Linseed oil by itself oxidizes and by employing the turpentine and naphtha petroleum solvent therewith the oxidation afiect is greatly reducedv The use of a solution M comprising two parts of turpentine and one part of linseed oil was also found to be satisfactory. A solution employing two parts of naphtha petroleum solvent and one part of linseed oil was found to be less satisfactory and the preferred solution of equal parts of linseed oil, turpentine and naphtha petroleum solvent was found to be the best for all around operation.

Preferably the shuttle block blanks l3 are immersed in the solution I4 for a period of the order of two hours. If they are permitted to be immersed in the solution for a longer period and particularly if allowed to be immersed until saturated, a higher pressure is required to densify the blank in a manner to be described hereinafter than when immersed for a shorter period.

After removal from the solution Hi, the blanks J3. are. allowed to dry ,for a period preferably of the order of two days. By employing such a long drying period, lower pressures for densifying the fibres are required than when the pressure step in the process described hereinafter is performed immediately upon removal of the blanks from the solution 14. In addition the longer drying time makes for less splitting and breakage of the blanks during the densifying process.

After drying for the period described above the prepared shuttle block blanks I3 are ready for densification which is accomplished by means of a hydraulic press generally designated at IT in the drawing. This press is illustrated as a vertical die generally designated at l8 mounted on a suitable base 19. The vertical die comprises two sections, an upper section lBa and a 1 lower section lb. The upper section 18a as is clearly shown in Fig. 3 of the drawings is a tapered rectangular die only to the extent that two sides only of the rectangular die are not parallel. The other two sides are parallel. With this arrangement it will be apparent that if a prepared shuttle block blank I3 is inserted into the upper tapered die l8a and forced therethrough one dimension of the cross section of the shuttle block I3 is reduced so as to densify the fibers thereof The parallel sides of the die are separated by. an amount equal to one dimension of the shuttle block blank 13 so that no compression of the fibers in this one dimension is occasioned, except as results indirectly from the compression of the other two sides of the shuttle block blank I3. For the specific shuttle block blank size mentioned above the die [8 is designed to convert the 2% inch by 1 /2 inch cross section to a 2 inch by 1 inch cross section. In other words, the

1 inch dimension is held constant.

For the purpose of heating the shuttle block to a desired predetermined temperature while the tapered die portion lBa is effective, the die portion la is surrounded by a jacket 20 which defines a suitable heat exchanger. A suitable heated fluid may be circulated through the heat exchanger through inlet and outlet openings designated as 2| and 22. A suitable fluid which might be circulated through the heat exchanger associated with the die portion l8a is oil, but it should be understood that any suitable means for heating the die portion i8a may be employed. For example, an electric heater, steam, or similar apparatus may be associated directly with the die 8a. Any suitable means for accurately controlling the temperature of the circulated fluid and consequently the temperature of the blank I3 while in the die portion l8a may be provided.

. a sscnoe It has been discovered that a temperature of the order of 220 F. is preferable- It will be understood that the hydraulic press I! also includes a suitable ram schematically illustrated at 23. Preferably the shuttle block blank I3 is forced into the die in the; manner indicated in Fig. 3 of the drawing by means of. the. ram 23. Then the ram 23,is withdrawn and: a metal rod or push bar small enough to pass through the die is inserted between the blank l3 and the ram 23 after which pressure is again applied forcing the block. all the way through the mold or die. i

The lower portion l 8b of the die .or mold l8 has the configuration-of the final cross section of the desired shuttle block l3: which is also. equal to the dimension. of. the exitof the die portion [8a. The. purpose. of .the lower die portion. l8b is to maintain. the. shuttle block l3; at the desired dimension while. removing the heat therefrom so that when. removed from the mold or die it. will retain. the desired dimension. Accordingly the die portionv l8b is also provided with a heat exchanger generally designated at 25 through which a suitable refrigerated brine solution or the like may be circulated. By circulating the cooling fluid through the heat exchanger 25 the shuttle block I3 is cooled so that when removed from the mold it maintains the desired crosssection with the densified portions along two edges thereof which will form the walls such as I20. and l2b of the final shuttle as shown in Fig. 1 of the drawing. In Fig. 3 of the drawing a shuttle block I3 is shown in its substantially completed form in the portion l8b of the die. A suitable blank [3' is shown being forced through the portion we of the die and a shuttle block blank I3 is shown just at the entrance of the die portion l8a. In this illustrated arrangement the successive shuttle blocks or blanks are employed as push rods for pushing the preceding shuttle block through the die. Preferably, and to avoid diificulty, however, a metal push rod is employed in the manner indicated above so that it is unnecessary to push one shuttle block blank by means of another.

It has been found that the total time which elapses from the moment the shuttle block blank is introduced into the mold until it emerges in completed form from the opening 21 in the base I9 averages slightly more than two minutes. The pressure required on the ram 23 varies from six to twelve tons with an average of about nine tons. It was found that if a high temperature were employed then a lower pressure is required. In such a case, however, more cooling is necessary to remove the larger quantity of heat. The specific values of pressure temperature and time mentioned above have been chosen to give the optimum performance although it should be understood that substantial variations of these variables may be employed.

The shuttle block l3 shown in Fig. 3 maintains its rectangular configuration throughout the process and it has the unique property of having a much greater density along two sides thereof, which two sides form the walls l2a and |2b of the finished shuttle shown in Fig. 1 of the drawing and a substantially lesser density along the other two walls, the greater part of which is routed out to form the chamber I2 for the bobbin mentioned above. The shuttle block I3 is therefore uniquely adapted for the manufacture of shuttles ID from common hardwoods such as hard maple, beech, birch and the like which are relatively plentiful and consequently will provide shuttle blocks which are. fully as: satisfactory if not more. satisfactory than. those made from dogwood. the. source of which is being rapidly depleted. The. process. described above while: especially desirable for making the object described is also: applicable for densifying wood generally where it is; desirable to densify it only in certain portions.

While there. has been illustrated. and described a. new and. improved article and process of making. the same, it. should be understood that various changes and modifications: thereof-will occur to: those skilled in the art, and it is intended in. the appended claims. to cover all those changes and modifications which fall within the true spirit andscope of the present invention.

What is claimed. as. new and desired tobe secured by Letters Patent. of the United States is l. The. process of mailing. shuttle block blanks.

which comprises immersing said blanks for a period of the order of two hours in a solution containing linseed oil, turpentineand a-naphtha petroleum solvent, applying a. pressure of from six to twelve tons longitudinally of each blank for moving said blank in the direction of the longitudinal axis thereof, applying a reducing force transversely of the direction of movement of said blank, maintaining a confining force transversely of'the moving blank in a direction substantially at right angles to the direction of both said movement and said reducing force "lereby to reduce the cross sectional area of the blank by reducing only one dimension of said cross section while maintaining the other dimension constant, heating said shuttle block blank to a temperature of the order of 225 F. while reducing said cross sectional area, and cooling said blank while maintained at said reduced cross sectional area to cause said blank to maintain said reduced cross section when said forces are no longer applied.

2. The process of densifying an elongated wood block which comprises immersing the wood block in a solution containing linseed oil, moving said block longitudinally, applying a reducing force transversely of said moving block in one direction, maintaining a confining force transversely of said moving block in a direction substantially at right angles to said one direction, whereby the cross sectional area of said block is reduced in only one dimension while the other dimension of said cross sectional area is maintained constant, heating said block while reducing the area of cross section thereof, and cooling said block while maintained at the reduced cross sectional area to a sufiicient extent to cause said block to maintain said reduced cross section when said forces are removed.

3. The process of densifying an elongated block of wood which comprises immersing said block in a solution comprising equal parts of linseed oil, turpentine and a naphtha petroleum solvent, applying a pressure longitudinally of said rectangular block to cause longitudinal movement thereof, applying a reducing force transversely of the direction of movement of said blank, maintaining a confining force transversely of the moving block and substantially at right angles to the direction of said reducing force whereby a reduction of the cross section of the block is obtained by reducing only one dimension of said cross section while maintaining the other dimension constant, heating said block during said movement, holding said reduced cross sectional area by maintaining said transverse forces, and cooling said block while maintained at the reduced cross section to cause said block to maintain said reduced cross section when said forces are released.

4. The process of densifying wood by forcing the same through a die having one portion capable of being heated and another portion capable of being cooled which comprises immersing for a period of the order of two hours an elongated rectangular block of hardwood in a solution comprising linseed oil', turpentine and a naphtha petroleum solvent, applying a pressure longitudinally of said elongated rectangular block to reduce the area of the cross section of the block while in said die by applying a reducing force transversely of the direction of movement through said die, maintaining a confining force transversely of the moving blank in a direction substantially at right angles to the direction of both said movement and said reducing force thereby to reduce only one dimension of said cross section while maintaining the other dimension constant, heating said block to a temperature over 200 F. while in said one portion of the die, moving said block to said other portion of said die where said reduced cross section is maintained, cooling said block while maintained at .the reduced cross section in said other portion of said die to cause said block to maintain said reduced cross section when removed from said die, and removing said block from said die.

JOHN ROSS CURTIS.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS 

